Author Topic: Have you converted your house?  (Read 53624 times)
wattMaster
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Re: Have you converted your house? « Reply #75 on: May 29, 2016, 09:36:50 PM » Author: wattMaster
Were reusable fuses a thing?
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Re: Have you converted your house? « Reply #76 on: May 29, 2016, 09:50:41 PM » Author: sol
There exists circuit breakers in the shape of a fuse, with a reset button. Those are meant to be used instead of fuses. What I'm referring to is real fuses that have blown and there are no spares around. Instead of going to the store, they just put a coin in the back to bridge the contacts in the socket. Very dangerous.

I have also seen 30 amp fuses used where 15 amp ones would be needed. Also dangerous. Circuit breakers solve those problems.
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Re: Have you converted your house? « Reply #77 on: May 29, 2016, 09:52:53 PM » Author: wattMaster
There exists circuit breakers in the shape of a fuse, with a reset button. Those are meant to be used instead of fuses. What I'm referring to is real fuses that have blown and there are no spares around. Instead of going to the store, they just put a coin in the back to bridge the contacts in the socket. Very dangerous.

I have also seen 30 amp fuses used where 15 amp ones would be needed. Also dangerous. Circuit breakers solve those problems.
Problems come when you get a short circuit or when the current gets too high for the resistance of the penny creating heat, And possibly melting anything nearby, causing a short circuit or a house fire.
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Re: Have you converted your house? « Reply #78 on: May 29, 2016, 11:58:27 PM » Author: Solanaceae
Oh yeah I have some inline medium base fuse holders that are like a j box mounted format, and there's an on off switch. I have wired it with 14g romex and a 15a screw in fuse. It serves as a supply for my experimental stuff so I'll just trip the Edison base breaker and not the room breaker.
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Re: Have you converted your house? « Reply #79 on: May 30, 2016, 02:34:31 AM » Author: Medved
And do you have GFCI/GFI sockets there?

Not sockets alone, but all circuits accessible via socket have to be GFCI (aka RCD) protected with sensitivity 30mA or below.
It does not mater, where the RCD is placed, but most installations have them in the main electrical panel.

Many people do not want to pay for more RCD's, which is still fine according to the code. For that limitation the best way I see is to use it for only the socket circuits, leave the lighting without the RCD (it is not required there).
Many electricians install it just on the main input, claiming it protects as well the lighting circuit, so therefore it "should be safer". Well,the electrical installation alone maybe, but the complete house isn't at all: When a hot watter kettle spills the water, it trips the common RCD and the complete house remains without any light. Then it is a question of time, when someone injures because of that...

Generally I do not like any common protection for many circuits: It goes against why the circuits are separated in the first place (= when fault happens, isolate that fault with least impact on the rest).
With the present material availability, I see the optimal method I see is to use the integrated circuit breaker + RCD for each circuit.They are not that much more expensive than a usual circuit breaker, while keeps the eventual fault isolated...
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Re: Have you converted your house? « Reply #80 on: May 30, 2016, 09:32:46 AM » Author: wattMaster
And do you have GFCI/GFI sockets there?

Not sockets alone, but all circuits accessible via socket have to be GFCI (aka RCD) protected with sensitivity 30mA or below.
It does not mater, where the RCD is placed, but most installations have them in the main electrical panel.

Many people do not want to pay for more RCD's, which is still fine according to the code. For that limitation the best way I see is to use it for only the socket circuits, leave the lighting without the RCD (it is not required there).
Many electricians install it just on the main input, claiming it protects as well the lighting circuit, so therefore it "should be safer". Well,the electrical installation alone maybe, but the complete house isn't at all: When a hot watter kettle spills the water, it trips the common RCD and the complete house remains without any light. Then it is a question of time, when someone injures because of that...

Generally I do not like any common protection for many circuits: It goes against why the circuits are separated in the first place (= when fault happens, isolate that fault with least impact on the rest).
With the present material availability, I see the optimal method I see is to use the integrated circuit breaker + RCD for each circuit.They are not that much more expensive than a usual circuit breaker, while keeps the eventual fault isolated...
How long do RCDs last? GFCI sockets here last about 10-30 years before they don't work anymore and are not up to code.
The reason every house has at least one "bad" GFCI is because they still provide power and the owners don't want the hassle of replacing an outlet for something they hopefully will never need.
« Last Edit: May 30, 2016, 09:34:40 AM by wattMaster » Logged

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Re: Have you converted your house? « Reply #81 on: May 30, 2016, 12:19:43 PM » Author: wattMaster
Quick update; We now have 3 LED chandalier lights in the ceiling fan with the lone CFL.
They are also Feit Electric bulbs.
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Re: Have you converted your house? « Reply #82 on: May 30, 2016, 03:14:45 PM » Author: hannahs lights
In my house we have upstairs and downstairs lights on separate 5 amp circuits wired in 1.5 mm cable sockrts upstairs are on a ring main wired in 2.5 mm cable fused at ,30 amps. Lounge ring main 30 amp dining room and Hannahs shack on 15 amp radial  kitchen half on spur from upstairs ring other half on same circuit as dinning room oh and I have 3 sockets on 15 amp fuse in my entertainment room AKA Hannahs private space
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Re: Have you converted your house? « Reply #83 on: May 30, 2016, 06:02:38 PM » Author: Ash
The system since 70s to this day is like :

Power input into lowest floor --> power company protections main for building --> power company protections for each user --> meter --> user panel with user's main breaker



The main power company potections use one-time cartridges with high interruption capacity - sand filled. They are slow-blow and rated so that the user's main breaker will allways trip before them. They are there in case there is a short circuit in the input to the user panel before the main breaker (damage to main cable) or in the meter, and to prevent users from swapping up their main breakers and overloading the grid

Officially they are supposed to be in a box with the power company's seal, the home owner is not allowed to access them

In reality, in most older (up to 80s) homes the box is not sealed, and the users do tamper with them occasionally. A common reason why they blow "and need tampering" is users swapping up the main breaker so it won't trip when they overload, or users connecting a circuit for a big load (most commonly water heaters) from before the main breaker



The user panel breakers are rewirable - You pull out the cartridge, connect a stretch of new fuse wire between the terminals, and plug it back in

In later years there appeared breakers that fit in the user fuse holders in place of the cartridge

I disassembled one of those replacement breakers - a BBC (the company is known as ABB nowadays) PicoSTOTZ - im not impressed. Contacts dont open very far apart, and the arc extinguishing measures are inferior to what is found in DIN rail breakers. It probably would work for the small short circuit currents in a house wired entirely with 1.5, but i would not trust this thing to open any significant short circuit, atleast without exploding while doing that..

I have somewhere a Soviet made version too, those are screw in shape and allmost fit an ordinary E27 socket, except the base contact is longer then in a lamp. The Soviet things are scary. The mechanics get stuck simply from pressing the reset/release buttons a few times, and definitely do if you press both buttons together, sometimes rendering the thing stuck for good in some middle position. The opening contact is a double contact type, so even after the bridgeing part is away from the main contacts, they are still next to each other. No arc extinguishing measures present at all. The trip mechanics are very rough and there are few things that can randomly fail and get stuck when its time to trip



In place of the coin hack were other variations :

In the rewirable fuses, users would connect a piece of Cu wire in the cartridge instead of the fuse wire, or would jumper around the fuse holder (add a wire connecting directly between the top and bottom terminals). I seen a 50s home in BeerSheva, the entrance floor panel there (multiple lighting circuits of the entrance and basement floors) looked like : Fuse holders of various sizes, in all of them the cartridges are missing, and there are bundles of 1.5mm^2 Cu wire stuck between the terminals around the cartridge

In the power company fuses, users would empty the cartridge (spill the sand out) and put in Cu wire, or wrap the blown cartridge as is with Al foil and screw it back in

With the Al foil, some peeps tried to use the Al coated paper from cigarette boxes... The metal in those things is very thin, and it does act as a fuse. Often setting fire to the paper while doing so



Lower floor of a 70s flats building (of a friend of mine). The panel contains the main power company fuses for the building and for the staircase/shelter, and a user panel for the staircase/shelter (that was worked on by some bright spark)

http://www.lighting-gallery.net/gallery/displayimage.php?album=2438&pos=43&pid=59845

60s fuse panel (found on the internet). The breaker box is a later addition, originally the sleeved wires from below (from the meter) were going straight into the fuse panel. Labels below fuses are (starting from left) : "Water Heater" "Appliances" "Appliances" "Lights" "Lights"

http://oi58.tinypic.com/2ngqssj.jpg



Well made RCDs normally last for decades - Many 70s RCDs are still around and are fine

I seen RCD failures and had the one in my panel fail too. The most common failure mode is random tripping for no reason, or being impossible to reset after it tripped once for a real reason. starts with trips once in a month, then becomes more common, then one day you simply cant reset it at all, even when it is out of the panel and not connected to anything - It would mechanically not click into the "on" position anymore

The "randomly tripping for no reason" thing is hard to troubleshoot, as the exact same behavior happens when the RCD is ok and is tripping for a reason. The way i troubleshooted it when mine started random tripping - First i measured many times the circuits on it for leaks. When i was not able to find anything, i replaced the RCD, and the tripping stopped

One common reason for RCD and any breaker failures is building debris that lands from the wall materials above the panel at time of construction or when messing with the wall and the panel is open. The dirt fallson the breakers and gets inside them into the mechanics, probably through the upper hole for the wire

Some years back i was called (as IT) to check for an office full of computers that blew all at once. I traced it down to a damaged 3 Phase RCD, that closed the Phase contacts but not the Neutral. The panel was full with phenomenal quantities of cement dust, some of which got inside the RCD and happened to stick on the Neutral switching contact pads, keeping them apart while the Phase contacts closed properly. This probably happened after the RCD tripped (for a reason), then a bit of dirt got to where it got, and somebody reset the RCD with the dirt inside



Code here requires RCD for all circuits at home including lighting. The most common setup is as Medved says, main current limiting breaker --> one RCD for all --> individual circuit breakers. Few peeps do install separate RCDs for separate circuits



Last night i had an event with the RCD tripping :

2AM everything is still fine, i switch off the computer, the light, and go to sleep. Morning the RCD is down. Something happened in the mid of the night..

The fault can be traced by measuring resistance L-PE and N-PE in each circuit (from the panel, with the power off). Measure DC voltage first (just in case, to not thunderbolt attack my multimeter with the charge from some Y capacitor somewhere, in Ohms measurement mode), then measure Ohms

L-PE in some circuits shows infinity, in some capacitance charging up and then infinity, and in some resistances. But it is possible that measuring like this is actually measuring a circuit like : L on the tested circuit - some load resistance (primary of a transformer or motor, ...) - N on the tested circuit - common N in panel - N on another circuit - Short is in the other circuit. So without separating the N's in the panel the results of this test are not much useable..

N-PE (all N are on the Neutral bar in the panel) shows single Ohms

Take out all the wires from N bar, measure each to PE. The offending circuit is one of the lighting circuits

Take apart the connections in the boxes this circuit goes to, measure each N to PE. the offender was a Fluorescent light in the bathroom. This also explains why L-PE showed nothing. The short was touching metal short N-PE. To the multimeter (measuring at very low voltage), the Fluorescent lamp and starter appear as open

The problem was, the metal edge of the back of the lantern was pressed hard into the N wire where it comes out of the wall, and it was punched through at the sharp point of the edge. It was installed there since about 1999..2000, The wire was probably pressed all along, but not punched through yet. I banged this light accidentally a few days before while replacing the shower curtain rod, and apparently this was the last push it took to punch through the isolation of the wire completely

I have a guess why it tripped the RCD last night and not allready back then :

Maybe the wire did not make very good contact in the point where it was punched through, and the small N-PE voltage present did not cause 30mA of leakage current

A momentary high load (fridge compressor starting ?) made the current there momentarily rise, possibly making some power dissipate there and improve the contact conductivity with each subsequent current pulse (think oxide layer on the lantern's metal breaking down ?)

After a few 10's times of such pushes, the contact eventually became good enough to conduct 30mA at the peak N-PE voltage, and that is when it tripped

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Re: Have you converted your house? « Reply #84 on: May 30, 2016, 06:52:38 PM » Author: wattMaster
What's N-PE and L-PE?
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Re: Have you converted your house? « Reply #85 on: May 30, 2016, 08:06:16 PM » Author: Ash
L - Phase
N - Neutral
PE - Earth

so, i poked the multimeter into L and PE or N and PE
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Re: Have you converted your house? « Reply #86 on: May 30, 2016, 08:30:13 PM » Author: wattMaster
L - Phase
N - Neutral
PE - Earth

so, i poked the multimeter into L and PE or N and PE
That's odd. Everyone here uses L for Line, N for Neutral and G for Earth/Ground.
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Re: Have you converted your house? « Reply #87 on: June 01, 2016, 02:45:36 AM » Author: Medved
@longevity of RCD's: Here the RCD's are not used that long, the code for a long time treated them only as an "additional protection" device, so one of the method considered "main protection" had to be used anyway:
Either PE connected to Neutral and so relying on the overcurrent protection to isolate the faulty equipment. This required grounding with so low impedance, it maintains safe voltage even when there is flowing maximum current of the outpet circuit breaker (so 10 or 15A at that time). With these the PE was grounded, as well as connected to Neutral, very frequently even combined with the Neutral into one conductor (PEN) in a form of TN-C (it went really to all sockets). This wiring had one specific: The PEN wire was required to be a solid wire from the panel to the last socket it served, so to connect an outlet, you have to strip longer section of the insulation and put that wire iunderneath both PE and N scews of the socket, without breaking/cutting the wire.
The other method, used for places with not that good grounding, has the PE not grounded, but in the main input is a special breaker, which monitors the voltage on that wire vs real ground and shuts off, when it exceeded 50V (maximum tolerance). The drawback was, things naturally grounded (equipment connected to piping, buried metal construction parts or so) was not possible to protect that way and there the only option was to ensure the grounding was made good enough (to conform to the overcurrent style).
Both of these methods were explicitely listed in the code, so one of them had to be always used, so it did not allow the RCD to be treated as a protection device.

It was only in 90's, when the Code changed it's phrasing to the more generic"automatic disconnection from a power source", which in fact meant the RCD becomes legal (it just a way of implementation of the "automatic power disconnection"; such as are the overcurrent or PE voltage monitor) as the main protection method.
Then only about in 2000 the RCD's became mandatory for the civil housings and it is only since that time, when they really become so wide spread to provide relevant reliability data. And it is not that long ago, so any overaged and so not working ones are not yet existent here.
The voltage monitors are in many places 50 years old or even older and still work well, at least those, that are regularly tested (it has a similar "test" button, connecting one of the line wires via a resistor to the PE to imitate the fault during the testing, as today's RCD's have).


L - Phase
N - Neutral
PE - Earth

so, i poked the multimeter into L and PE or N and PE
That's odd. Everyone here uses L for Line, N for Neutral and G for Earth/Ground.

There are systems, where the PE is not grounded, yet it is a part of the protection against presence of dangerous voltages on accessible metal parts. E.g. the voltage sensing method, or some insulated systems (mainly in hospitals,...), where the power source is not grounded, nor is the PE, yet interconnection of all accessible metal objects is required.
So to not confuse such safety interconnection with real grounding, the interconnection is called "PE" and not "Grounding".
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Re: Have you converted your house? « Reply #88 on: June 01, 2016, 08:04:45 AM » Author: Ash
The RCD failures i seen were not related much to their age

The one that failed in my panel was maybe 5 years old. The one i put in its place is a used 80s one, that still works to this day (passes the test button tests)

The one with the open Neutral in the office was maybe a few months new, it failed as result of abuse, and maybe not so good ingress protection design



The TN-C to the socket is a dangerous method - Broken PEN wire, without any additional fault, places 230V on the enclosures of all connected equipment

In addition, if there is some device that provides metal connection between PEN and outside Earth (like the washing machine) it is hard to predict what current will go there (through water pipes, ..) to the outside Earth in normal condition. And it will carry all the load current (possible from multiple apartments..) in case of broken PEN. I see a potential for fire there
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Re: Have you converted your house? « Reply #89 on: June 01, 2016, 09:30:44 AM » Author: wattMaster
The RCD failures i seen were not related much to their age

The one that failed in my panel was maybe 5 years old. The one i put in its place is a used 80s one, that still works to this day (passes the test button tests)

The one with the open Neutral in the office was maybe a few months new, it failed as result of abuse, and maybe not so good ingress protection design



The TN-C to the socket is a dangerous method - Broken PEN wire, without any additional fault, places 230V on the enclosures of all connected equipment

In addition, if there is some device that provides metal connection between PEN and outside Earth (like the washing machine) it is hard to predict what current will go there (through water pipes, ..) to the outside Earth in normal condition. And it will carry all the load current (possible from multiple apartments..) in case of broken PEN. I see a potential for fire there

And what's TN-C and PEN?
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